1. Field of the Invention
This invention relates to a distributive communications network, and to a node therefor. The invention is particularly applicable to an optical fibre network.
2. Related Art
The existing `fixed access` networks, such as public switched telephone networks (PSTNs) and cable television networks, fall into two distinct topologies driven by different customer requirements. A PSTN has a `star` topology with a central node or exchange and a tiered access structure. It is designed for bi-directional real-time speech communications. Cable television networks have been developed to provide unidirectional (broadcast) services to customers. They have a `tree-and-branch` or switched star topology.
A known distributive communications network node has a first input path, and power divider means connected with the first input path and arranged to split incoming traffic on the first input path along a local output path and a wider area output path.
It has been recognized that it would be desirable to be able to provide an integrated broadband switched network for applications ranging from basic telephony through to data and high definition television signal transmission. One result of this recognition is the broadband integrated services digital network (B-ISDN). However, a significant factor, neglected by most B-ISDN studies, is the cost of implementing the necessary transmission and switching infrastructure for a national system.
Known optical broadband telecommunication networks utilize wavelength division multiplexing (WDM) techniques (see IEEE Communications Magazine, Vol. 29, No. 3, March 1989, pages 22 to 30, and Journal of Lightwave Technology, Vol. 9, No. 12, December 1991, pages 1702 to 1716).